It is well known in motor vehicles to provide a seat belt system for restraining an occupant in the vehicle seat. The seat belt system typically includes a retractor having a spring biased reel which winds the shoulder belt to a taut condition about the occupant A reel locking mechanism is conventionally provided and is responsive to a sensed condition of vehicle deceleration to lock the reel against belt unwinding rotation.
It is also known in such vehicle brake systems to provide a pyrotechnic device or spring device associated with the wheel and adapted to forcibly retract the belt in order to tension the belt around the occupant.
Furthermore is it known to provide a tension relieving mechanism associated with the seat belt retractor and including a lock bar engageable with the belt reel to prevent belt rewinding by the wind-up spring so that the belt is held at a slackened condition about the vehicle occupant.
It is also known in motor vehicles to provide an antilock brake system in which sensors associated with the vehicle wheels communicate with an electronic control unit which determines the onset of an incipient wheel lock condition and then controls the vehicle brake system to alternately release and reapply the brakes.
In addition, it is known in the prior art to connect the brake pedal of the vehicle to the seat belt retractor so that the retractor is locked whenever the driver applies the brakes.
It would be desirable to provide a seat belt system in which restraint of the occupant by the belt system would be initiated in response to the wheel condition sensed by the antilock brake system.